Gripping attachment for backhoe or excavator

ABSTRACT

A backhoe or excavator is adapted for use in lifting and transporting objects such as logs, beams, and the like, by a gripping attachment that functions in conjunction with the backhoe bucket. The gripping attachment consists of one or more, preferably two, plates that have a scalloped contact edge in the form of a series of convex curved protrusions while the protrusions themselves are arranged in a concave curve. The attachment is mounted or capable of being mounted to the surface of the boom at a location a short distance above the pivot axis of the bucket on the side of the boom that is also faced by the bucket opening. When the bucket is thus rotated back toward the attachment, an object to be lifted or transported can be securely held between the bucket and the scalloped edge with no damage to the surface of the object.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention resides in the field of materials handling equipment that is used in the construction industry or other industries where earth moving is involved or the loading of materials is needed. In particular, this invention addresses components or attachments for use on backhoes or excavators that render the equipment usable for lifting heavy objects.

2. Description of the Prior Art

Various types of equipment are designed for scooping, lifting, moving, and depositing material such as sand, soil, gravel, and mud. Of these, the term “backhoe” generally refers to a power-operated boom with a normally vertical arm that is pivotally mounted to the boom and a rectangular bucket that is pivotally mounted to the arm. The boom, arm and bucket are able to pivot in combination within a single plane, forward or back, and in many cases the bucket can be pivoted laterally as well. The term “loader,” or particularly “front loader,” generally refers to a tractor that has a wide rectangular bucket mounted to its front end. The term “loader backhoe” generally refers to a tractor that has a loader with a wide rectangular bucket on the front and a backhoe on the rear, the backhoe being able to swing right or left over a range of about 200 degrees. The term “excavator” generally refers to a backhoe whose entire upper structure can rotate right or left over a range of 360 degrees. The term “backhoe or excavator” is used collectively herein to refer to any of these types of equipment.

In some cases, a backhoe or excavator is used for transporting heavy objects to or from a worksite. Objects that are often transported in this manner include structural components, logs, boulders, blocks and the like, often with decorative surfaces or features. A gripping claw or thumb is positioned on the equipment at a location close to the bucket such that the claw or thumb and the bucket together can grasp the object from both sides. Descriptions of claws or thumbs or other structures that allow a backhoe or excavator to grasp an object in this manner are found in the following United States patents:

-   -   U.S. Pat. No. 4,407,626 to Bruckner, P. J., issued Oct. 4, 1983     -   U.S. Pat. No. 4,519,739 to Risch, J. V., issued May 28, 1985     -   U.S. Pat. No. 4,770,597 to Powers, R. S., issued Sep. 13, 1988     -   U.S. Pat. No. 4,804,309 to Risch, J. V., issued Feb. 14, 1989     -   U.S. Pat. No. 5,111,602 to Risch, J. V., issued May 12, 1992     -   U.S. Pat. No. 6,203,267 B1 to Heiple, A., et al., issued Mar.         20, 2001     -   U.S. Pat. No. 6,209,237 B1 to Heiple, A., et al., issued Apr. 3,         2001

The contents of these patents are incorporated herein by reference.

When a backhoe or excavator is used in this manner, it is important that a solid grip on any object be maintained. For many objects, however, it is also important to avoid damage to the object or to its surface. When logs are transported by these devices, for example, it is important not to pierce the log surface in such a manner that the log adheres to the gripping members but rather to allow the log to be released by simply separating the members. When decorative boulders and polished building materials are transported, it is important to avoid scratching or otherwise defacing the surface.

SUMMARY OF THE INVENTION

The present invention resides in an attachment to the boom of a backhoe or excavator that operates in conjunction with the bucket to grip large or heavy objects but has a distinct profile that offers a number of advantages over the thumbs and claws of the prior art. The attachment includes one or more plates having an exposed edge oriented to face the bucket opening when the bucket is pivoted back toward the boom. (In the claims hereto, the word “a” denotes “one or more.”) The edge has a scalloped shape formed by a series of convex (i.e., outwardly curved) protrusions arranged along the edge, each protrusion forming a smooth curve with no sharp points exposed, thereby allowing only the curved edges contact the object. In addition, the edge itself forms a generally concave curve, i.e., the extremities of the protrusions, which are the outermost sites along each individual protrusion that are closest to, and capable of contacting, the object, follow a line that describes a concave curve. In this way, at least two of the protrusions contact the object, and for curved objects such as logs or cylindrical or spherical objects in general, the series of protrusions generally follow the curvature of the object to reduce the chances of slippage.

In preferred embodiments of the invention, the attachment consists of two or more plates arranged in parallel orientation, preferably with scalloped edges curved and oriented in the same manner so that both plates operate in conjunction for further prevention of slippage. The plates can be joined by a connecting or base plate, optionally with additional transverse plates for dimensional stability, to form a unitary structure. The plate (or plates) is designed for secure attachment to the boom with no moving parts such as pivot pins, positioning pins, struts or arms. There is therefore no need for maintenance and no deterioration of the parts due to wear. The attachment allows the boom and bucket to grasp the object and to lift it, maneuver it, and place it securely without damage to the surface of the object or to the object itself.

Still further embodiments, features, and advantages of the invention will be apparent from the description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a backhoe bearing a gripping attachment in accordance with the present invention, showing the attachment together with the bucket and the end of the boom adjacent to the bucket.

FIG. 2 is a side view of the components shown in FIG. 1 with the bucket folded up to grasp a log between the bucket and the gripping attachment.

FIG.3 is a perspective view of the gripping attachment of the embodiment shown in FIG. 1.

FIG. 4 is a side view of the gripping attachment of the embodiment shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

While the concepts and features that define the present invention can be implemented in a variety of configurations and constructions, a general understanding of these concepts and features can be gained by a detailed study of one particular embodiment. The attached drawings and the following description focus on one such embodiment.

FIG. 1 depicts the end of a backhoe showing the bucket 11, the boom 12 to which the bucket 11 is attached, an arrangement of piston and cylinder, pivot pins, and connecting rods for manipulation of the bucket, and the gripping attachment 13 of the present invention. The piston 14 and cylinder 15 are powered by hydraulics and a power source (not shown), and govern the movement and position of various rods 16, 17 and a series of four pivot pins 18, 19, 20, 21 and additional rods 20, 21 forming a bucket link. These components enable the bucket 11 to pivot along the arc indicated by the arrow 22, drawing the bucket opening toward or away from the gripping attachment 13. FIG. 2 shows the bucket 11 drawn toward the gripping attachment 13 so that the two operate together to grasp a log 23.

FIG. 3 is an enlarged view of the gripping attachment, showing the two parallel plates 31, 32 of the preferred embodiment, a base plate 33 to which the two plates are mounted and which is in turn mounted to the surface of the boom 12 (FIGS. 1 and 2), and a transverse stabilizing plate 34 for further rigidity. The two plates in this embodiment are identical, and the profile of one of the plates is shown in FIG. 4. The profile shows that the contacting edge of the plate is scalloped, which in the context of this invention means that the edge is formed of a series of protrusions 35, each of which is curved in a convex direction. The protrusions in this embodiment are half circles, each with a smooth round contour such that no jagged or pointed edges are present. The protrusions are regularly spaced, although irregular spacing is also acceptable. The edge itself on the larger scale is curved in a concave curve, such that the extremities 36 (the outermost points) of the protrusions define the curved line represented by the dashed line 37 in the Figure. The curvature of this line is not critical to the invention and can vary widely. In most applications, a curvature that is an arc of a circle will be preferred, particularly an arc that is equal to or less than one-fourth of the circumference of the circle. Likewise, the number of protrusions along the edge of the plate can vary. While six protrusions are shown in the plates in these Figures, the number is not critical to the invention. In most cases, an appropriate number will lie within the range of 3 to 20, or preferably 4 to 10.

The various plates of the gripping attachment can be joined by conventional means, such as bolting, welding, machining, or the like, and entire attachment can likewise be secured to the boom 12 through the base plate 33 by any of these methods as well. The securement of the base plate 33 to the boom can be either a permanent securement or a detachable securement.

The foregoing is offered primarily for purposes of illustration. Further variations in the contours, shapes, and relative dimensions and sizes that are still within the scope of the invention will be apparent to those skilled in the art. 

1. A gripping member for attachment to a backhoe or excavator having a boom and a bucket pivotally mounted to said boom, said gripping member comprising: a plate having a scalloped edge in the form of a plurality of convex curved protrusions positioned at intervals along said edge, the extremities of said protrusions collectively forming a concave curve, and securing means for securing said plate to said boom.
 2. The gripping member of claim 1 comprising two or more of said plates, and wherein said securing means secures said plates to said boom in a parallel orientation.
 3. The gripping member of claim 2 wherein said securing means is a base plate joining said plates to form a unitary structure.
 4. The gripping member of claim 1 wherein said scalloped edge consists of from 3 to 20 of said convex curved protrusions.
 5. The gripping member of claim 1 wherein said scalloped edge consists of from 4 to 10 of said convex curved protrusions.
 6. The assembly of claim 2 wherein said concave curve formed by said extremities of said protrusions is an arc of a circle equal to one-fourth of the circumference of said circle or less. 